Covering panels consisting of extruded, laterally interlocking elements have been designed to overcome these practical and aesthetic drawbacks. Such panels are described, for example, in U.S. Pat. Nos. 3,085,367 and 4,063,396, as well as German Patent Application No. DE-A-1 297 836. However, these panels are not particularly easy to attach, since each panel must be individually fastened to a conventional supporting structure, which is a complicated, expensive and unwieldy procedure.